Brain anatomical correlates of mobility control in the oldest old

描述（由申请人提供）：居住在社区的老年人经常报告与心肺、肌肉骨骼、外周和中枢神经系统的多因素变化相关的活动障碍。有强有力的紧急证据表明，白质（WM）高强度与下肢活动受限相关，独立于其他因素。罗萨诺博士最近发现，速度和平衡受损与特定活动相关区域的局灶性灰质（GM）萎缩有关。本纵向流行病学项目旨在调查来自健康老龄化身体成分研究（Health ABC）的社区老年人大队列中GM和WM局灶性脑磁共振成像（MRI）异常与年龄相关的步态速度和平衡活动障碍的纵向关联。该建议建立在目前正在进行的健康大脑项目（K23AG028966-01, PI: Dr Rosano）的基础上，该项目是对250名健康ABC队列参与者的定量脑mri测量与活动能力之间关系的描述性横断面研究。我们提出的这项新研究将通过获取额外的148个MRI来增加检测重要影响的能力，并将通过增加脑MRI完成后3年的随访时间，进一步纵向了解脑MRI异常对活动障碍自然史的影响。因此，在2006-2007年卫生ABC研究计划的数据收集阶段，这项建议的时机独特，可以获取重要信息。该项目使用自动体积法、磁化传递和扩散张量成像来测量GM和WM异常的严重程度和位置。该项目的目的是：1。研究局灶性区域性GM和WM束异常与活动能力恶化，特别是与步态速度和平衡的纵向关联。2. 探讨GM/ WM异常组对恶化速度和平衡的综合影响。3. 确定心血管危险因素与运动相关区域和动脉束局灶性GM和WM异常的纵向关联。该项目的结果将促进我们对社区老年人行动障碍发病机制的了解，并将为进一步研究与行动控制有关的神经网络的年龄相关变化奠定基础，例如使用功能性脑MRI研究。

DESCRIPTION (provided by applicant): Community-dwelling older adults often report mobility impairment linked with multifactorial changes in the cardiopulmonary, musculoskeletal, peripheral and central nervous systems. There is strong emergent evidence that white matter (WM) hyperintensities are associated with lower-extremity mobility limitations independent of other factors. Dr. Rosano has recently discovered that impaired speed and balance are associated with focal grey matter (GM) atrophy of specific mobility-related regions. This longitudinal epidemiological project aims to investigate the longitudinal association of focal brain magnetic resonance imaging (MRI) abnormalities in GM and WM with age-related mobility impairment in gait speed and balance in a large cohort of community-dwelling older adults from the Health Aging Body Composition Study (Health ABC). This proposal builds onto the current ongoing Healthy Brain Project (K23AG028966-01, PI: Dr Rosano), which is a descriptive cross-sectional study of the association between quantitative brain MRIs measures and mobility in 250 participants of the Health ABC cohort. The new study that we propose will increase the power to detect important effects via the acquisition of additional 148 MRIs and will provide further longitudinal insights into the impact of brain MRI abnormalities on the natural history of mobility impairment by adding a follow up time of 3 years after completion of brain MRI. Thus, this proposal is uniquely timed to capture important information during the planned data collection phase of the Health ABC Study in 2006-2007. This project uses automated volumetric methods, magnetization transfer and diffusion tensor imaging to measure severity and location of GM and WM abnormalities. The aims of this project are: 1. To examine the longitudinal association of focal regional GM and WM tracts abnormalities with worsening mobility and specifically with gait speed and balance. 2. To examine the combined effect of groups of GM/ WM abnormalities on worsening speed and balance. 3. To determine the longitudinal association of cardiovascular risk factors with focal GM and WM abnormalities in mobility-related regions and tracts. The results of this project will advance our knowledge of the pathogenesis of mobility impairment in community-dwelling older adults and will lay the ground work for further studies of age-related changes of the neural networks involved in mobility control, for example using functional brain MRI studies.